Search results for " CRA"

Molecular Structure of the Arthropod Hemocyanins

1992

Hemocyanin is an extracellular, blue protein that occurs in high concentrations in the blood of many arthropods, including spiders, scorpions, horseshoe crabs, crustaceans, and at least two centipedes. Serving as an ### oxygen carrier, it is functionally equivalent to hemoglobin, but performs reversible oxygen binding between two copper ions. Hemocyanin is composed of a number of subunits that assemble in an extremely large macro-molecular entity. These particles, which are similar in size to viruses or ribosomes, exhibit a complex allosteric behavior during oxygen binding. There is growing evidence that this functional plasticity has evolved upon, and answers to, ecophysiological constrain…

A comparison of the impacts of introduced signal crayfish and native noble crayfish in boreal lake ecosystems

2014

A comparative molecular dynamics-phase-field modeling approach to brittle fracture

2016

Abstract In this work, a novel comparative method for highly brittle materials such as aragonite crystals is proposed, which provides an efficient and accurate in-sight understanding for multi-scale fracture modeling. In particular, physically-motivated molecular dynamics (MD) simulations are performed to model quasi-static brittle crack propagation on the nano-scale and followingly compared to macroscopic modeling of fracture using the phase-field modeling (PFM) technique. A link between the two modeling schemes is later proposed by deriving PFM parameters from the MD atomistic simulations. Thus, in this combined approach, MD simulations provide a more realistic meaning and physical estima…

Evaluation of user experience goal fulfillment

2014

In this paper, the results of a user experience (UX) goal evaluation study are reported. The study was carried out as a part of a research and development project of a novel remote operator station (ROS) for container gantry crane operation in port yards. The objectives of the study were both to compare the UXs of two different user interface concepts and to give feedback on how well the UX goals experience of safe operation, sense of control, and feeling of presence are fulfilled with the developed ROS prototype. According to the results, the experience of safe operation and feeling of presence were not supported with the current version of the system. However, there was much better suppor…

Investigation of buckling characteristics of cracked variable stiffness composite plates by an eXtended Ritz approach

2021

Abstract Variable Angle Tow (VAT) composite plates are characterized by in-plane variable stiffness properties, which opens to new concepts of stiffness tailoring and optimization to achieve higher structural performance for advanced lightweight structures where damage tolerance consideration are often mandatory. In this paper, a single-domain eXtended Ritz formulation is proposed to study the buckling behaviour of variable stiffness laminated cracked plates. The plate behaviour is described by the first order shear deformation theory whose generalized displacements, namely reference plane translations and rotations, are expressed via suitable admissible trial functions. These consist of a …

Teacher educators' collective professional agency and identity : Transforming marginality to strength

2017

Abstract This study investigated teacher educators' collective professional agency and identity within an identity coaching programme. The participants in the programme were teacher educators from the field of arts and crafts education. Through a shared process involving increased trust and togetherness, the teacher educators became empowered in terms of their collective identity and agency. The study points to the importance of addressing individual narratives and learning pathways in seeking to understand emergent collective agency and identity in professional contexts. Our theoretical contribution includes an advanced understanding of collective identity and agency, and of their close re…

Georeferenced cartography dataset of the La Fossa crater fumarolic field at Vulcano Island (Aeolian Archipelago, Italy): conversion and comparison of…

2011

The present study illustrates the procedures applied for the coordinate system conversion of the historical fumarole positions at La Fossa crater, to allow their comparison with newly acquired global positioning system (GPS) data. Due to the absence of ground control points in the field and on both the old Gauss Boaga and the new UTM WGS 1984 maps, we had to model the transformation errors between the two systems using differential GPS techniques. Once corrected, the maps show a residual Easting shifting, due to erroneous georeferencing of the original base maps; this is corrected by morphological comparative methods. The good correspondence between the corrected positions of the historical…

Optimal die Design for Cold Extrusion Processes

1999

The design of cold extrusion processes requires the optimisation of several process variables in order to obtain a defect free product. The fulfilment of different objectives, such as the minimisation of forming loads or the homogeneity of the deformations, is highly requested. Nevertheless, several other relevant aspects of extrusion processes have to be taken into account and require a suitable optimisation of the process parameters and in particular of the die shape. In this paper, tool life has been assumed as the most relevant goal and an effective die design procedure as been setup. It is well known that fatigue cracking of the dies is the principal cause of dies failure in cold extru…

Influence of the process variables on the product distribution and catalyst decay during cracking of paraffins

1986

Abstract The influence of the partial pressure of the hydrocarbon, reaction temperature, time on stream and the presence of olefins on the product distribution and the kinetics and decay during the cracking of n-heptane on an REHY zeolite were studied. It was found that the isomerization to cracking ratio depends on the hydrocarbon partial pressure. The active sites for cracking and isomerization are not the same and those for cracking decay faster, the selectivity changing with the degree of decay of the zeolite. The protolytic to β-cracking ratio, and therefore the paraffin to olefin ratio, are a function of the partial pressure of n-heptane. Both reactants and products have a marked infl…

Self-assembly properties of the proteinaceous coat secreted by the ?slime? variant of Neurospora crassa

1989

The proteinaceous extracellular material (PEM) synthesized by the cells of the ‘slime” strain of Neurospora crassa (see Martinez et al. 1989) was solubilized by treatment with urea or guanidine. Removal of these chemicals by dialysis, caused reassembly of the solubilized proteins into material with the same microscopic appearance as the original PEM. Polypeptide patterns from both native and reassembled structures were identical. Dialysis-mediated reassembly of the solubilized proteins appeared to be dependent on both concentration of the soluble macromolecules and time. Gel chromatography of PEM solubilized with different agents revealed two discrete populations of complexes with molecular…